JP2008134111A - Thermal resistance measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten an exchange time from a measurement completion time point until the next sample exchange, and to improve measurement efficiency and accuracy of a thermal resistance measuring device. <P>SOLUTION: This thermal resistance measuring device for determining a thermal resistance from a temperature difference between the surface and the back of a measuring sample 3, and the heat quantity by sandwiching the measuring sample 3 between a heating shaft 1 and a cooling shaft 2, is equipped with: cooling jackets 4, 8 installed respectively on the heating shaft 1 and the cooling shaft 2, wherein a coolant flows; a cooling fan 56 provided on the back of the heating shaft 1 and the cooling shaft 2, for blowing cooling air to the heating shaft 1 and the cooling shaft 2; a divided heat insulating material 6 placeable to enclose the heating shaft 1 and the cooling shaft 2; and a heat insulating material moving mechanism for moving the heat insulating material 6. After sandwiching the measuring sample 3 between the heating shaft 1 and the cooling shaft 2, the heat insulating material 6 is moved to enclose the heating shaft 1 and the cooling shaft 2 by the heat insulating material moving mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermal resistance measuring apparatus that sandwiches a measurement sample between a heating shaft and a cooling shaft, allows a desired amount of heat to flow through the sample, and obtains a thermal resistance value or the like from a temperature difference between the front and back surfaces.

  For example, in order to improve the cooling performance of CPUs for computers and small electronic components, polymer materials such as heat conductive grease and heat conductive sheets are frequently used, and their development is actively performed. For this reason, an evaluation apparatus that can accurately evaluate thermal physical properties such as thermal resistance and thermal conductivity of the thermal conductive grease or the thermal conductive sheet is used.

JP 2003-121397 A

  In the thermal resistance measurement device that measures the thermal resistance and thermal conductivity with high accuracy, such as the thermal grease and thermal conductive sheet as in the above prior art, when measuring many samples continuously, the temperature of the measuring part must be The time for lowering to the desired temperature is long and the measurement efficiency is low.

  An object of the present invention is to solve the above-described problems of the prior art, shorten the exchange time from the end of measurement to the next sample exchange, and improve the measurement efficiency and accuracy of the thermal resistance measurement device.

  In order to achieve the above object, the present invention sandwiches a measurement sample between a heating axis and a cooling axis, flows a desired amount of heat from the heating axis in the direction of the cooling axis, and detects the temperature difference and the amount of heat between the front and back surfaces of the measurement sample. In the thermal resistance measurement device for obtaining the thermal resistance of the measurement sample from the cooling jacket, which is attached to the opposite side of the measurement sample to the measurement sample side of the heating shaft and the cooling shaft, and is provided behind the heating shaft and the cooling shaft. A cooling fan that blows cooling air to the heating shaft and the cooling shaft; a heat insulating material that can be installed so as to surround the heating shaft and the cooling shaft; and a heat insulating material movement that moves the heat insulating material. And after the measurement sample is sandwiched between the heating shaft and the cooling shaft, the heat insulating material surrounds the heating shaft and the cooling shaft by the heat insulating material moving mechanism. It is intended to be moved into.

  According to the present invention, since the heating shaft and the cooling shaft after the measurement can be cooled at high speed, the time for exchanging the measurement sample can be greatly shortened, and the measurement efficiency can be improved. Moreover, when measuring the same sample continuously, since the time from the end of the first measurement to the start of the next measurement is shortened, the measurement error can be reduced.

An overall configuration of a thermal resistance measuring apparatus according to an embodiment of the present invention will be described.
In FIG. 1, four support columns 21 and a Z-axis stage 13 are fixedly installed on a base plate 22, and a digital gap detector light emitting unit 11, a digital gap detector 12, and an upper plate 15 are fixed to the support column 21. A load cell 10 is attached to the plate.
The intermediate plate 17 has a structure that can move in the vertical direction along the support column 21. The intermediate plate 17 includes a heating shaft 1, a heating shaft side heater block 5, and a heating shaft side cooling jacket 4 (for example, made of thin metal And a heating unit comprising a heating shaft side heat insulating material 6 is fixedly installed. In addition, a cooling unit comprising a cooling shaft 2, a cooling shaft side heater block 7, a cooling shaft side cooling jacket 8 and a cooling shaft side heat insulating material 9 is fixedly installed on the Z-axis stage 13. Further, the heating shaft 1 and the cooling shaft 2 are provided with a plurality of thermocouples for measuring the temperature gradient of each shaft.

Moreover, it is desirable that the surfaces of the heating shaft 1 and the cooling shaft 2 that sandwich the measurement sample 3 are the same and have the same area (for example, the area that sandwiches the measurement sample is 10 mm ² ). Since the measurement value is affected in a state where the occurrence of the phenomenon occurs, it is necessary to fabricate so that both surfaces are in uniform contact.
The safety cover 14 is L-shaped so as to cover the front and left and right portions of the measurement portion, and is attached to prevent injury during measurement and burns during high temperature measurement. Although the material is not specified, any material having heat resistance that can withstand the set temperature of the measurement sample 3 may be used. It is preferable to use aluminum or acrylic, and the measurement is not affected at all.
When the measurement sample temperature is 50 ° C. or higher during the movement of the Z-axis stage 13 and during the measurement operation and even after the measurement is completed, the safety cover is prevented from being removed.

  The shaft periphery heat insulating material is installed so as to surround the heating unit and the cooling unit. The heat insulating material to be used is made of, for example, a material having high hardness based on glass fiber.

FIG. 2 is a connection diagram of the thermal resistance measuring device main body 34 and peripheral devices.
The control unit 36 mainly takes in the temperature data of the heating shaft 1 and the cooling shaft 2 and transmits it to the personal computer 35, and the reference zero contact for setting the temperature reference for the thermocouple attached to the heating shaft 1 and the cooling shaft 2. It includes a control device such as a device, a sequencer that controls the measurement operation, and a DC stabilized power source that controls based on the set power. The thermal resistance measuring device main body 34 and the control unit 36 are connected by seven cables 25 to 31. Of these, 30 and 31 are used for data management of measured temperatures sent from the thermocouple. In addition, the thermostatic chamber 38 supplies the refrigerant to the thermal resistance measuring device main body 34 by two water distribution tubes (32, 33) for input and output. On the way, the amount of water is adjusted through the flow rate adjusting valve 37 to the output water distribution tube 32.

  FIG. 3 shows the structure of a cooling unit and a heating unit. First, a heating shaft side heater block 5 is connected to the surface of the heating unit on the side opposite to the measurement part of the heating shaft 1 so that the thermal resistance is reduced. The heating shaft side cooling jacket 4 is connected. The heating shaft side cooling jacket 4 is provided with an inlet / outlet for allowing the refrigerant to flow into the heating shaft side cooling jacket 4. Similarly, a cooling shaft side heater block 7 and a cooling shaft side cooling jacket 8 are connected to the surface of the cooling unit opposite to the measurement portion of the cooling shaft 1 so that the thermal resistance is reduced. The cooling shaft side cooling jacket 8 is provided with an inlet / outlet for allowing the refrigerant to flow into the cooling shaft side cooling jacket 8.

  Next, how the refrigerant flows into the cooling jacket will be described. The temperature-controlled refrigerant from the thermostatic chamber 38 is divided by using the flow rate adjusting valves 39 and 40 to adjust the flow rate flowing through the heating shaft side cooling jacket 4 and the cooling shaft side cooling jacket 8 so as to obtain a desired amount. To do. The diverted refrigerant flows through each cooling jacket, thereby receiving heat accumulated in the heating unit and the cooling unit, increasing the temperature, flowing out from each cooling jacket, and returning to the thermostatic chamber 38.

The structure of the heat insulating material and the mounting position of the cooling fan will be described with reference to FIGS. FIG. 5 is an AA arrow view of FIG.
The heat insulating material is divided into four parts and is installed so as to surround the heating shaft 1 and the cooling shaft 2. However, in FIG. 5, the cooling shaft 2 is not shown because it is hidden by the heating shaft 1. Each of the shaft peripheral heat insulating materials 49, 50, 53, 54 is provided with a moving handle 47, 48, 51, 52 for moving the heat insulating material. This moving handle has a screw-in structure, so it can be easily attached to and detached from the heat insulating material around the shaft.

The heating shaft 1, the cooling shaft 2 and the measurement sample 3 are composed of four shaft peripheral heat insulating materials 49, 50, 53,
54 and is visible only from the gap. There is a gap between the front left heat insulating material 49 and the front right heat insulating material 50, but there is very little, and the same is true between other heat insulating materials. Furthermore, since it is almost shielded from the outside air by the safety cover 14, it takes a lot of time for the temperature of the measurement sample 3 to drop after the measurement is completed.

  The cooling fan 56 (for example, about 40 mm in length and width and desirably about 10 mm in thickness) is installed outside the heat insulating material around the shaft and behind the heating shaft 1 and the cooling shaft 2. Although only one cooling fan 56 is shown behind the heating shaft 1 in order to cool the heating shaft 1 with the highest temperature, a plurality of cooling fans 56 may be installed along the heating shaft 1 and the cooling shaft 2. As shown in FIG. 6, the cooling fan 56 is attached to the back cover 55, and the back cover 55 is fixed to the base 22.

Next, the movement method of the shaft periphery heat insulating material after the measurement is completed will be described with reference to FIGS. FIG. 7 shows a state in which the moving handles 47, 48, 51, 52 are pulled in the horizontal direction after the measurement is completed. FIG. 8 is an AA arrow view of FIG.
By pulling the moving handles 47, 48, 51, 52 to the left and right, the shaft peripheral heat insulating materials 49, 50, 53, 54 move in the lateral direction, and an air flow path is formed around the heating shaft 1 and the cooling shaft 2. Is done. By providing this air flow path, the cooling air from the cooling fan 56 flows smoothly around the heating shaft 1 and the cooling shaft 2, and the temperature of the heating shaft 1 and the cooling shaft 2 can be quickly cooled. It becomes possible. However, in FIG. 8, the cooling shaft 2 is not shown because it is hidden by the heating shaft 1. In addition, although the case where the operation | movement which pulls a handle for a side is performed manually was demonstrated, of course, it is sufficient to move with a motor etc.

Next, the measurement principle of the thermal resistance measuring device will be described with reference to FIG.
When a constant amount of heat Q is passed from the heating shaft 1 to the cooling shaft 2 with the measurement sample 3 sandwiched between the heating shaft 1 and the cooling shaft 2, a temperature distribution (gradient) is generated between the heating shaft 1 and the cooling shaft 2. appear. This temperature distribution is detected by, for example, thermocouples 41 to 46 that are placed at a constant distance from the tip on the side sandwiching the measurement sample of each axis and are attached at equal intervals. The number of thermocouples is three for each of the heating shaft 1 and the cooling shaft 2 in FIG.

From the measured temperature distribution, the temperature Th of the contact portion between the heating shaft 1 and the measurement sample 3 and the temperature Tc of the contact portion between the cooling shaft 2 and the measurement sample 3 are estimated. By doing so, the thermal resistance R of the measurement sample including the contact thermal resistance of the interface can be obtained. This is expressed as follows.
R = (Th−Tc) / Q
The measurement method will be described below with reference to FIGS.
By raising the Z-axis stage 13, the measurement surface of the cooling shaft 2 is brought close to contact with that of the heating shaft 1.
The digital gap detector 12 detects a state where a certain load is applied and the measurement surfaces of both axes are in contact with each other and positions it as the zero reference. After that, how much has changed from the zero state during measurement. Display.

  Next, the Z-axis stage 13 is lowered to sandwich the measurement sample between both axes. The position to be lowered can be set arbitrarily, but it is desirable to lower it to a position that takes into consideration workability. The measurement sample 3 is aligned in advance with the same dimensions as the measurement surfaces of both axes so that the applied heat quantity is reliably transmitted to the measurement sample. Also, due to the material of the measurement sample, the surface shape, etc., for example, if the surface irregularities are noticeable, it was determined that air would enter the gap when directly contacting the measurement surface of both axes, and the measurement value of the measurement sample itself could not be calculated accurately In this case, the measurement is performed in a state where grease having a very low thermal resistance is applied as a buffer material to the measurement sample and the measurement surfaces of both axes. In that case, the thermal resistance value of grease or the like used in advance is measured with this apparatus, and the thermal resistance value of the measurement sample itself is obtained by subtracting the value from the thermal resistance value calculated as the measurement result of the measurement sample.

After placing the measurement sample 3 on the measurement surface of the cooling shaft 2, the Z-axis stage 13 is raised and brought into contact with the measurement surface of the heating shaft 1. In this state, when the measurement sample 3 protrudes or is displaced from the position between the two axes, the Z-axis stage 13 is lowered again and reset. After confirming that the measurement sample 3 is normally sandwiched, the heat insulating material around the shaft is installed so as to surround each shaft. The measurement is started from a point in time when predetermined measurement conditions are satisfied. After the measurement, heating by the heater block of the heating unit and the heater block of the cooling unit is stopped.
The shaft peripheral heat insulating materials 49, 50, 53, 54 are manually moved outward using the moving handles 47, 48, 51, 52, and the cooling fan 56 is operated.
A refrigerant is passed through the heating shaft side cooling jacket 4 of the heating unit and the heating shaft side cooling jacket 8 of the cooling unit. Thereby, the heating axis | shaft 1, the cooling axis | shaft 2, and the measurement sample 3 after completion | finish of a measurement can be cooled at high speed.

When the measurement sample becomes 50 ° C. or lower, the Z-axis stage 13 is lowered, the safety cover 14 is removed, the measurement sample 3 is taken out, and the measurement data is automatically stored in the personal computer 35 in a file format.
By repeating the above operation, a large number of measurement samples are measured.
According to this measurement method, the heating shaft 1, the cooling shaft 2, and the measurement sample 3 after the measurement can be cooled at high speed, so that the measurement sample replacement time can be greatly shortened and the measurement efficiency can be improved. Further, when measuring the same sample continuously, the time from the end of the first measurement to the start of the next measurement is shortened, so that the measurement error is reduced.

The side view which shows the thermal resistance measuring device main body which is one embodiment by this invention. The block diagram of the thermal resistance measuring apparatus which is one embodiment. The block diagram which shows the cooling unit and heating unit which are one Embodiment. The side view which shows the shaft periphery heat insulating material position at the time of a measurement. AA arrow sectional drawing of FIG. The side view which shows the cooling fan attachment position which is one Embodiment. The side view which shows the shaft periphery heat insulating material position at the time of cooling. AA arrow sectional drawing of FIG. Explanatory drawing which shows the measurement principle of a thermal resistance measuring apparatus.

Explanation of symbols

1 Heating shaft 2 Cooling shaft 3 Measurement sample 4 Heating shaft side cooling jacket 5 Heating shaft side heater block 6 Heating shaft side heat insulating material 7 Cooling shaft side heater block 8 Cooling shaft side cooling jacket 9 Cooling shaft side heat insulating material 10 Load cell 11 Digital gap Detector light emitting unit 12 Digital gap detector 13 Z-axis stage 14 Safety cover 15 Upper plate 16 Linear bush 17 Intermediate plate 18 Length meter mount 19 Length meter stage 20 Intermediate fixed base 21 Body support 22 Base plate 23 to 31 Connection cable 32, 33 Water distribution tube 34 Thermal resistance measuring device body 35 Personal computer 36 Control unit 37 Flow rate adjusting valve 38 Constant temperature bath 39, 40 Flow rate adjusting valves 41 to 43 Heating shaft side thermocouples 44 to 46 Cooling shaft side thermocouple 47 Handle for moving (front left) side)
48 Moving handle (front right)
49 Axial insulation (left front side)
50 Axis insulation (right front side)
51 Moving handle (left rear side)
52 Moving handle (right rear side)
53 Axial insulation (left rear side)
54 Thermal insulation around the shaft (right rear side)
55 Back cover 56 Cooling fan

Claims (5)

A thermal resistance for obtaining a thermal resistance of the measurement sample from the temperature difference and the heat quantity between the front and back surfaces of the measurement sample by sandwiching the measurement sample between the heating axis and the cooling axis, flowing a desired amount of heat from the heating axis in the direction of the cooling axis In the measuring device,
A cooling jacket that is attached to each side of the measurement sample opposite to the heating shaft and the cooling shaft;
A cooling fan that is provided behind the heating shaft and the cooling shaft and blows cooling air to the heating shaft and the cooling shaft;
A heat insulating material that can be installed so as to surround the heating shaft and the cooling shaft;
A heat insulating material moving mechanism for moving the heat insulating material;
After the measurement sample is sandwiched between the heating shaft and the cooling shaft, the heat insulating material is moved so as to surround the heating shaft and the cooling shaft by the heat insulating material moving mechanism. A thermal resistance measuring device.   2. The heat insulating material according to claim 1, wherein the heat insulating material is moved by the heat insulating material moving mechanism after the measurement of the thermal resistance of the measurement sample, opens an enclosure between the heating shaft and the cooling shaft, and A thermal resistance measuring apparatus, wherein a cooling air flow path from the cooling fan is formed around the cooling shaft.   2. The heat insulating material according to claim 1, wherein the heat insulating material is moved by the heat insulating material moving mechanism after the measurement of the thermal resistance of the measurement sample, opens an enclosure between the heating shaft and the cooling shaft, and The thermal resistance measuring device, wherein the cooling shaft is cooled with cooling air from the cooling fan, and the cooling jacket refrigerant is flowed to cool the heating shaft, the cooling shaft, and the measurement sample.   The thermal resistance measuring device according to claim 1, wherein the heat insulating material is divided into four parts.   2. The thermal resistance measuring apparatus according to claim 1, wherein a plurality of the cooling fans are installed along the heating axis and the cooling axis.

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